如何在 ViewModel 中使用 RadDragAndDrop 事件

Question

我正在将 telrik RadDragAndDrop 工具与 ListBox 一起使用。我正在使用 silverlight 和 mvvm light。我的问题是我应该如何在 ViewModel 中使用这段代码。这是一个代码隐藏文件。

 public Construtor()
    {
        InitializeComponent();
        RadDragAndDropManager.AddDragQueryHandler(this, OnDragQuery);
        RadDragAndDropManager.AddDragInfoHandler(this, OnDragInfo);
        RadDragAndDropManager.AddDropQueryHandler(this, OnDropQuery);
        RadDragAndDropManager.AddDropInfoHandler(this, OnDropInfo);
    }
    private void OnDropInfo(object sender, DragDropEventArgs e)
    {
        ItemsControl box = e.Options.Destination as ItemsControl;
        IList<Section> itemsSource = box.ItemsSource as IList<Section>;
        Section section = e.Options.Payload as Section;

        if (e.Options.Status == DragStatus.DropComplete)
        {
            if (!itemsSource.Contains(section))
            {
                itemsSource.Add(section);
            }
        }
    }

    void OnDropQuery(object sender, DragDropQueryEventArgs e)
    {
        ItemsControl box = e.Options.Destination as ItemsControl;
        IList<Section> itemsSource = box.ItemsSource as IList<Section>;
        Section section = e.Options.Payload as Section;
        e.QueryResult = section != null && !itemsSource.Contains(section);
    }

    void OnDragInfo(object sender, DragDropEventArgs e)
    {
        ListBoxItem listBoxItem = e.Options.Source as ListBoxItem;
        ListBox box = ItemsControl.ItemsControlFromItemContainer(listBoxItem) as ListBox;
        IList<Section> itemsSource = box.ItemsSource as IList<Section>;
        Section section = e.Options.Payload as Section;
        if (e.Options.Status == DragStatus.DragComplete)
        {
            if (section != null && itemsSource.Contains(section))
            {
                itemsSource.Remove(section);
            }
        }
    }

    protected virtual void OnDragQuery(object sender, DragDropQueryEventArgs e)
    {
        ListBoxItem listBoxItem = e.Options.Source as ListBoxItem;
        ListBox box = ItemsControl.ItemsControlFromItemContainer(listBoxItem) as ListBox;
        if (e.Options.Status == DragStatus.DragQuery && box != null)
        {
            e.Options.Payload = box.SelectedItem;
            ContentControl cue = new ContentControl();
            cue.Content = box.SelectedItem;
            e.Options.DragCue = cue;
        }
        e.QueryResult = true;
    }

    private void button1_Click(object sender, RoutedEventArgs e)
    {
        SelectingQuestionsWindow window = new SelectingQuestionsWindow();
        window.Show();
        this.radExpander1.Visibility = System.Windows.Visibility.Visible;
    }

<*XAML*> 这是我的 Xaml。

        <ListBox x:Name="SectionListBoxMain" Height="165" Width="200" SelectedItem="{Binding SelectedSectionList}"
                        DisplayMemberPath="SectionName" ItemsSource="{Binding SectionList}" ItemContainerStyle="{StaticResource draggableItemStyle}">

            <telerik:RadDragAndDropManager.AllowDrop>
                true
            </telerik:RadDragAndDropManager.AllowDrop>

        </ListBox>

        <TextBlock Width="20" />

        <ListBox x:Name="SectionListBox" Height="167" Width="200" ItemsSource="{Binding SelectedSectionList}" telerik:RadDragAndDropManager.AllowDrop="True" DisplayMemberPath="SectionName" ItemContainerStyle="{StaticResource draggableItemStyle}">

            </ListBox>

    </StackPanel>

Answer 1

这是视图逻辑，并不真正属于您的 ViewModel。它可能更适合行为。

请参阅此示例： http://www.telerik.com/help/silverlight /raddraganddrop-within-radgridview.html

他们使用行为并将其附加到网格以启用行重新排序。您可以从以下内容开始：

public partial class ListDragDropBehavior : Behavior<ListBox>

您需要添加一些依赖属性以绑定到其他列表框。

然后，您可以通过简单地将其附加到列表框来在其他列表框中使用此行为（我使用混合来附加行为）